Stabilizing oscillation generators



March 11, 1924. mwsm K. W. WAGNER SIIABILIZ ING OS C ILLATION-GENERATORS Filed June 28. 1925 avwamtoz KARL WILLY WAGNER his awe 1mgAlaEBICA, A COH/PGEATIOEI' DELA'WABE.

Application filed June 28,

To all whom it may concern:

Be it known that l, KARL WILLY WAGNER, a citizen of Germany. and aresident of lesches Uter 12/1 3, Berlin, S. W. ll, many, have inventednew and useful improvements in Stabilizing Oscillation Cronerators (forwhich have filed an application in Germany, Get. I l, 1921)., of whichthe following is a specification accompanied by drawings.

This invention relates to an arrangement for stabilizing the operationof oscillation generators which are utilized with tuned or untuned load.

Generators adapted for the production of mechanical, acoustic,electrical, or other oscillations and waves are often used with loadswhich are tuned to a definite frequency, or else to a more or lessnarrowly limited frequency range, this plan being either followed forthe purpose of utilizing; such oscillation generators most etllcientlyor for the purpose of excluding the tran mission to the load orconsuming devices of secondary oscillations of the generator. However,in this connection certain ditiicuh ties are often encountered due tothe reaction of the load upon such oscillation genorator, whichdifficulty among other things manifests itself by an alteration of the:ire quency produced, the consequencebeing that the generator ceases tobe tuned to the load dealt with, and that it fails to yield its fullpower. Moreover, such change in the frequency is generally veryundesirable.

In accordance with German Patent No. 28%,603 the said reaction producedby the tuned load upon the oscillation generator is reduced by theinclusion of resistance in the load whereby the resonance curve of thelatter is enlarged; however, the advantage so gained is only realized atthe expense of selectivity of the consuming device or load. The samething holds good of the ar rangeinent described in German Patent No.298,482 in which the enlargement of the resonance curve is attained by atwo-wave characteristic of the load. It has also been suggestedtodissyntonize the load with relation to the oscillation generator, butthis gives up the advantages realized by the tuning between the load andthe generator.

Now, according to the present invention the deviation of the oscillationgenerator is 1923. Serial No. 6%8,81l.

prevented by providing it with a supplemental load which is externalwith relation to the syntonized or primary load, a supplemental load isutilized which depends upon the frequency, in such a man nor that thesupplemental load is low inside the range of the working frequency,while it increases greatly soon as the frequency departs from theworking range in either an upward or downward direction. llhat isrealized thereby is that the total load of the generator is subject tobut little change with the frequency, the generator beby this means ridof its tendency to deviate with relation to the load.

The invention is illustrated in the accompanying diagrams in which Fig.1 is a diagrammatic representation of a circuit embodying the invention.

Fig. 2 is a modification of Fig. 1 in which the supplemental load isdependent upon the frequency range of the generator.

Fig. 3 is a curve illustrating the characteristics of the arrangementshown in 2; and

Fig. l is an arrangement in which the load is substantially independentof the frequency.

Referring to Fig. l, is an electric oscillation generator which carriesa syntonized or primary load circuit B.

The supplemental load consists of an inductance L and a capacity Cconnected in parallel therewith, the circuit LC being tuned to excludethe working frequency, hence, for this frequency it possesses a veryhigh impedance and it takes as a consequence only very small current.Above and below the tuning frequency, the impedance of the said circuitis much lower so that the generator in the presence of a deviation ofthe frequency from its normal value becomes subject to a largesupplemental load which increases with the departure "from suchfrequency. By appropriate adjustment or proportioning of resistance R ordamping of the circuit LC, the value ofthe supplemental load can beregulated. The efi'ect of: the damping is to flatten the resonance curveoi? the tuned circuit LC and to increase the energy losses in thesupplemental load which would be zero in the ideal case where theinductance has no resistance and the condenser has no lOU energylosseswhen current flows there-' through is designated by the term damped.

The manner in which stabilization occurs in this as well as in the othermodifications may be illustrated by an example. Assume the generator (ito be an alternator operating at a frequency of 50,000 cycles deliveringcurrent to tuned or untuned load B at this frequenc and assume a changein the load to occur which tends to decrease the speed of the alternatorwith the result that the frequency tends to decrease correspondingly. Itthen results that there is a tendency for the load to receive a frequency lower than that at which it should be operated. This tendency fora decrease in frequency is prevented by tuning the circuit LC so that itexcludes the frequency of 50,000. If the frequency departs from 50,000at which the circuit LC is avery high or approaches an infiniteimpedance, its impedance rapidly decreases and tends to pass a heavycurrent therethrough. This would result in a greatly increased totalload on the generator.

It is well-known, however that a generator will operate in such a mannerthat it will tend to work at the frequency or under the conditions atwhich the minimum load is imposed thereon. This is true regardlcss ofwhether the load is principally reactance or largely resistance.- Ittherefore follows that the frequency will not reach a value at which thecircuit LC imposes a heavy load on the generator and the latter willtherefore maintain a frequency close to 50,000. The range will depend toa certain extent on the resistance of the circuit LC which tends toflatten the resonance curve.

There are cases where it is demanded that the supplemental load shouldbecome effective only upon the working frequency departing from adefinite range included within two limiting values ml and Q2. As long asthis range is relatively narrow, an arrangement as depicted in F 1 willprove adequate, circuit LC being tuned to a value intermediate between(01 and (02. However, to obtain a rapid increase of load at the limitingvalues (91 and c2 when there is a wider range between these a convenientarrangement is to connect two, or if necessary, more circuits LlCl,LQLEZ, in series, as indicated in Fig. 2. These circuits aredissyntonized with relation to each other. Fig. 3 illustrates andexplains the operation of this scheme. Curve 1 illus trates thedependency of the impedance of the circuit LiCl on the frequency; curve2 the same condition with respect of circuit- LQCQ. The total impedanceof the supplemental load contained between points a and 6 results as.the sum of the partial impedances and is illustrated in Fig. 3 by theheavy curve. The same is high inside the frequency range m1, m2, and asa. result the supplemental load is low while at the limiting values ofthe range it drops rapidly to the desired low value so that a ltlrtifisupplemental load is applied.

The operation of. this arrangement is similar to that of Fig. 1. By thismethod a convenient means is provided for flatten ing the resonancecurve of the supplemental load to enable it to be effective over a widerrange of frequencies.

The arrangements as hereinbefore described can be used to advantage alsoin cases where the useful load itself is independent of the frequency,but where be tween the generator and the useful load an arrangementselective in action is disposed which is intended to prevent undesirablesecondary oscillations of the generator from getting into the consumeror load. This results in the total load having the combined propertiesof the filter system and the useful load which latter is independent offrequency. That is, the load on the generator then acts as though itwere substantially tuned on account of the selectivity or tuning of thefilter system. An arrangement of this sort is illustrated by way ofexample in Fig. 4, the consumer consisting here of a long line whichserves for the transmission of the waves set up by the generator, theline being assumed to be a consumer possessing a practically constantimpedance w. The line is in the case before us provided with a chainfilter connected in series with it, the purpose of the same beingtoexclude secondary oscillations set up by the generator from the line.

The filter which may be of any suitable well-known type consisting forexample of series tuned circuits L3C3; L464; L565; L (3",; L', 6' L 6'adapted to readily pass the working frequency. 'An inductance Lconnected in shunt between 0 and C, and an inductance L in shunt withthe series tuned circuits are adapted to shunt the secondaryfrequencies.

The consuming circuit made up of the chain filter and line possesses theproperties of a markedly selective load on the oscillation generator,and this occasions operating difficulties of the kind mentioned'at theoutset; but these are avoided by the provision of a supplement load Z ofthe kind previously described.

Having described my invention What I claim is 1. An arrangement forstabilization of 0scillation generators comprising in combination anoscillation generator adapted to operate Within a particular Workingfrequency range, a primary load connected thereto Which is substantiallyindependent of said Working frequency; a filter connected between saidload and said oscillation generator for passing the Working frequencyand excluding secondary harmonic or undesired frequencies produced bysaid generator whereby the load imposed on said generator assumes thecharacteristics of a load tuned to the working frequency, and asupplemental stabilizing load connected to said generator, saidsupplemental load consisting of an oscillation circuit for substantiallyexcluding the Working frequency and imposing an increased supplementalload on the generator at nearby frequencies.

2. An arrangement for stabilization of oscillation generators comprisingin combination an oscillation generator adapted to operate Within aparticular Working frequency range, a primary load connected theretowhich is substantially independent of said Working frequency; a filterconnected between said load and said oscillation gener' ator for passingthe Working frequency and excluding secondary harmonic or undesiredfrequencies produced by said generator whereby the load imposed on saidgenerator assumes the characteristics of a load tuned to the Workingfrequency and a supplemental stabilizing load connected to saidgenerator between the filter and the generator, said supplemental loadconsisting of an oscillation circuit for substantially excluding theWorking frequency and imposing an increased supplemental load on thegenerator at nearby frequencies.

KARL VVILLY WAGNER.

